In the synthesis of VLSI designs, built-in test controllers are often implemented. Some modules (such as memories) have a much higher defect density than other types of logic. Memories normally implement additional and comprehensive testing. One conventional approach is to test such memory modules by using a test controller placed on a chip. Comprehensive testing often means performing a number of tests. Such tests often become cumbersome to combine into one test controller.
It would be desirable to implement a test controller that may receive downloadable tests. The downloadable tests may be implemented in the form of a program that may be downloaded into the test controller and executed during the test runtime.